250 



R. L. KITCHELL 



The presence or absence of a response to distilled water in the chorda 

 tympani and glossopharyngeal nerves determined whether or not distilled 

 water could be used as the solvent for other test solutions. Liljestrand and 

 Zotterman (1954) observed in animals in which a response to distilled water 

 was present, that if Ringer's solution was applied shortly after the tongue 

 had been washed with Ringer's solution, no neural response followed the 

 second application of Ringer's solution. They recommended using 



DOG CHORDA TYMFANI NIRV! 



1 i i i i l ! i ! i i . 1 i I - ! 1 



1 SEC. 



Fig. 13. Records from whole chorda tympani of a dog. Recording procedures 

 same as in Fig. 1 1 . Ringer's solution applied before each test solution. A, 0.5 m 

 sodium chloride. B, 0.46 m sucrose in Ringer's solution. C, 0.02 m quinine 

 hydrochloride in Ringer's solution. D, 0.2 m acetic acid (Kitchell, unpublished). 



Ringer's solution as the solvent for the test solutions and the procedure of 

 applying Ringer's solution prior to the application of a test solution to 

 estabhsh a " base line " of spontaneous activity in the nerve. This proce- 

 dure was followed in the experiments to be discussed here except in those 

 animals where no distilled water response could be elicited. In these 

 animals distilled water was used as the solvent and was applied to the 

 tongue shortly before the test solution was applied. 



The test solutions routinely used were 0.5 m sodium chloride, 0.46 M 

 (15 per cent) sucrose, 0.02 m quinine hydrochloride and 0.2 m acetic acid. 



